%I A118814
%S A118814 1,2,5,18,70
%N A118814 Number of 'tree-like curves' with n intersection points, useing the definition 
               in V. I. Arnold's "Topological Invariants of plane curves and caustics", 
               page 12.
%C A118814 The objects being enumerated are a subset of those enumerated by A008983. 
               The restriction involved is that the gauss diagram (or chord diagram)has 
               no intersecting chords. The first 3 entries are the same as A008983 
               because, for less than 3 intersection points, all curves are tree-like. 
               For 3 intersection points there are only 2 curves that are not tree-like. 
               They appear as the 4th and 15th entries in the table for n=3, on 
               page 14 of Arnold's book. ( For all I know, this sequence may be 
               equal to one of the others allready in the database with the same 
               initial terms.)
%Y A118814 Cf. A008983.
%Y A118814 Sequence in context: A150023 A150024 A150025 this_sequence A014271 A073157 
               A141494
%Y A118814 Adjacent sequences: A118811 A118812 A118813 this_sequence A118815 A118816 
               A118817
%K A118814 nonn
%O A118814 0,2
%A A118814 Moshe Newman (mshnoiman(AT)gmail.com), May 23 2006